A Research On Clinical Practice And Three-dimensional Pre-operative Planning Of Knee Surface Displacement

SectionⅠ. Three-dimensional Reconstruction before the Knee Surface Displacement and computer assisted designObjectives: To measure the patient's knee joint by means of three-dimensional spiral CT imaging and probe on the possibility of Mimics 10.01 reconstruction technique based on the knee of patients. To make the pre-operative planning with Mimics software and the features of knee anatomy on the basis of three-dimensional spiral CT imaging material and to ensure that the displacement of surface prosthesis could renew the lower limb axis and joints as normal.Methods: Spiral CT scan, a thick layer of 0.5 mm, the scanning range of the CT scan covers from hip joint to ankle joint, and we could obtain the precise cross-sectional image of knee , and then carry out the three-dimensional reconstruction through putting the information into Mimics reconstruction software, reconstruct the complete skeleton structure of knee through automatic or manual thresholding. Extract one side of the model of the knee based on the different thresholding of different parts. Extract the cloud data of patient's ankle and shin bone, the application of the stimulation knee and make the pre-operative planning including the ideal angle of laying the prosthesis, lines of force reconstruction, osteotomies parameters through three dimensional computer measurement. Outcome: Obtain the accurate model of knee joint after the vector processes of the materials gained by CT scan, make the pre-operative planning based on the three-dimensional imaging reconstruction. The advantages of this method are as follows: the location of knee lower limb axis and osteotomies guidance can be easier and more accurate, a quicker pre-operative X-ray location and a better demonstration of three-dimensional characters of the patient's lateral femoral condyle compared with the traditional methods , and guarantee an accurate measurement instead of pre-operative X-ray measurement .Conclusion: To realize the three-dimensional reconstruction based on CT two-dimensional materials, and imitate successfully the reconstruction model of knee joint, make pre-operative planning and scheme, carry out accurate osteotomy and guide the TKR operation.SectionⅡ. The Clinical Application of Three Dimensional Pre-operative PlanningObjectives: Designing digital operation model, and implement pre-operative planning in clinical cases. After the operation, observe and measure through X-ray and CT image, and make a comparison with the precision and clinical effect of prosthesis locating results in the regular operation.Methods:The are two testing groups, and they are differed based on the method mentioned above and the traditional method. The first group is the group of pre-operative planning: (1) From 2006 January to 2011 January, 40 cases have been selected (12 males 28 females) from 55~77 years old with the average age 64.7. These patients who need TKR have no other operation contraindication diseases. The common clinical symptoms of these patients are knee deformity, knee pain, difficulty to walk, knee activities limited and all these problems influence their work and life. All the patients have received the 16 row helical CT scan, the pre-operative planning has been made including the ideal angle of laying the prosthesis, lines of force reconstruction, osteotomies parameters through three dimensional computer measurement as we mentioned above.(2) From 2006 January to 2011 January, one chief physician in our hospital made several operations of knee displacement for 40 patients (16 males 24 females) at the same period under the same condition, and their age ranged from 51 to 76 years old with the average age 63.6. All the pre-operative checks were the same as the first group. According to the comparison between short-term curative effect, AKS evaluation before and after operation, the HKA, we do the relevant statistic analysis in order to explain the advantages of pre-operative three-dimensional planning in the guidance of operations.Outcome: There were 40 patients in pre-operative three-dimensional planning group, 30 patients had good effects, 8 groups had comparatively good effects, 2 patients had moderate effect, no patient had poor effect, the good effect rate was 95%. There were also 40 patients in traditional planning group, 24 patients had good effects, 8 patients had comparatively good effects, 8 patients had moderate effect, no patient had poor effect, the good effect rate was 80%. Meanwhile, patients in three-dimensional planning group recovered much better than traditional group in the ankle and limbs activities. After setting the prosthesis, patients acted well in stretching the knee, checking the range motion of the knee and the kneecap.Conclusion:Pre-operative three-dimensional planning and traditional planning are both methods in TKR. Pre-operative three-dimensional planning could lead to a relatively ideal outcome in the clinical experiments, and it have more advantages in all aspects than traditional planning. On this account, precise osteotomy is an ideal method in TKR, and it is worth clinical spread.